Untersuchung der Kinetik der Strukturbildung und der thixotropen Eigenschften paraffinhaltiger Dispersionssysteme

Ohne Zusammenfassung     

Die Stabilität der Kobalt(II)- und Kupfer(II)-Komplexe mit α-, β- und γ-Aminobutyrat

Stability constants of cobalt(II) and copper(II) complexes with α-, β-, and γ-aminobutyrate as well as the protonation constants of these ligands have been determined by potentiometric titration. ΔG ^? values, computed from the stability constants, increase in the orderAABA. The increase in ΔG ^? AABA→BABA amounts approx. 15 per cent. The same difference was observed for α- and β-alaninato complexes with various transition metal ions.     

Furan derivatives-IX : A convenient new method of arylation of furan reaction of diazoaminobenzenes with furan and isopentyl nitrite

A convenient new method for the arylation of furan with derivatives of diazoaminobenzene and isoamyl nitrite is described. Using this method the substituted 2-(X-phenyl)furan derivatives, where X is H, 4-CH₃, 4-Cl, 4-Br, 3-Cl, 3,4-diCl, 4-NO₂, 4-COOCH₃, 4-COOH, 4-Cl-3-CF₃ and 2-(3-pyridyl)furan were prepared. The reaction of methyl 4-aminobenzoate with furan and isopentyl nitrite gave (besides 2-(4-carbmethoxyphenyl)furan) 4,4′-dicarbmethoxydiazoaminobenzene, the structure of which was proved by mass spectrometry and by synthesis. This diazoaminobenzene derivative was unstable in the reaction medium and with isopentyl nitrite and furan at 30° gave 2-(4-carbmethoxyphenyl)furan. The mechanism of the reaction is discussed.     

Beitrag zur mikroskopischen Identifizierung organischer Stoffe nach L. Kofler. V

Zusammenfassung In Fortsetzung früherer Untersuchungen zum Zweck der Ergänzung und Erweiterung der Identifizierungs-Tabelle nachKofler werden für 62 Substanzen die thermomikroskopischen Konstanten mitgeteilt und die gegebenenfalls notwendigen Zusatzreaktionen beschrieben. Bei Nicotinamid, das auf Grund seiner Fähigkeit, mit vielen Stoffen wie organischen Säuren, Säureestern, Phenolen u. a. Komplexverbindungen zu bilden, häufig als Reagens in Betracht kommt, wird das polymorphe Verhalten erläutert und das Auftreten von sieben Modifikationen beschrieben.

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Contribution to the microscopic identification of organic materials after L. Kofler. V

Summary In continuation of earlier investigations for the purpose of supplementing and extending the identification tables ofKofler, the thermomicroscopic constants are given for 62 substances and when necessary the supplementary reactions are described. In the case of nicotinamide, which because of its ability to yield among other things complex compounds with organic acids, acid esters, phenols, is frequently considered as reagent, the complex behavior is illustrated and the occurrence of 7 modifications is described.

     

Extraction du césium. sous forme de tétraiodobismuthite,par le nitrobenzéne

Caesium can be extracted from aqueous solutions with a solution of tetraiodobismuthite in nitrobenzene. The optimum conditions for the extraction have been studied. Caesium can be separated from most important fission products.     

Analytische Aspekte der Oxydation organischer Stickstoffverbindungen mit Chromsäure. II

Zusammenfassung Eine Halbmikromethode zur Bestimmung der an Kohlenstoff oder Sauerstoff gebundenen Nitro- und Nitrosogruppen in organischen Verbindungen wurde ausgearbeitet. Die Methode beruht auf dem oxydativen Aufschluß der Substanz mit einem Chromsäure—Schwefelsäure-Gemisch, wobei die Nitro- und Nitrosogruppen quantitativ in Salpetersäure übergehen. Diese wird mit Devarda-Legierung in alkalischem Medium zu Ammoniak reduziert, das dann im Stickstoffstrom abdestilliert und acidimetrisch titriert wird.

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Summary A semimicro method for determining nitro- and nitroso groups attached to carbon or oxygen in organic compounds has been worked out. The method is based on the oxidative decomposition of the sample with a chromic acid-sulfuric acid mixture, the nitro and the nitroso groups being quantitatively transformed into nitric acid. The latter is reduced to ammonia by means of Devarda alloy in alkaline medium, and is then distilled off in a stream of nitrogen and titrated with a standard acid solution.

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Résumé On a mis au point une méthode à l'échelle semimicro pour le dosage dans les substances organiques de groupes nitro et nitroso liés au carbone ou à l'oxygène. La méthode repose sur l'attaque oxydante de la substance par un mélange acide chromique-acide sulfurique, ce qui transforme quantitativement les groupes nitro et nitroso en acide nitrique. Au moyen de l'alliage de Devarda en milieu alcalin, on réduit celui-ci en ammoniac que l'on chasse par distillation dans un courant d'azote et que l'on titre par acidimétrie.

     

Indazoles in organic synthesis: Formation of some fused heterocycles

Derivatives of pyrimido(1,2-b)indazole and s-triazino(1,2-b)indazole were prepared by several different routes and some transformations are described.     

Spin-adapted wave functions of the serber type and time reversal

A procedure is proposed for generating Serber-type spin eigenfunctions withM _s = 0. The procedure uses the time-reversal invariance of these functions to increase the efficiency and to reduce the storage requirements. Simplifications in calculating the matrix elements of an observable operator which follow from the use of the time-reversal symmetry are briefly discussed.     

Studium des gegenseitigen Einflusses der Bindungen in Thiocyanat-Kupfer(II)-Komplexen mit Methyl- und Dimethylpyridinen mittels Infrarotspektroskopie

The infrared spectra of thiocyanato-copper(II) complexes of the type Cu(NCS)₂ L ₂ with all isomeric picolines and lutidines (L) as well as those of the type Cu(NCS)₂ L ₃ withL=3- and 4-picoline, 3,4- and 3,5-lutidine were measured. The behaviour of the (CN) stretching vibrations of the Cu(NCS)₂ L ₂ complexes led to conclusions on the different kind of coordination of the NCS groups in dependence on the ligandL. The mutually conditioned strength of the Cu–NCS and Cu–N(L) bonds in the equatorial plane, especially in the presence of ligandsL with the steric effect, was determined from the frequency shift of the Cu–NCS and Cu–N(L) stretching vibrations with regard to the vibrations for Cu(NCS)₂(pyridine)₂.

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